From 184dc70be483e4fe2cbf11acd1c8523467eb8ec9 Mon Sep 17 00:00:00 2001
From: masterelmar <18119527+masterElmar@users.noreply.github.com>
Date: Tue, 12 Dec 2023 12:48:44 +0100
Subject: [PATCH] fix:#82 added multithreaded fetching

---
 backend/sport/main.go | 65 +++++++++++++++++++++++++++++++++----------
 1 file changed, 50 insertions(+), 15 deletions(-)

diff --git a/backend/sport/main.go b/backend/sport/main.go
index b62e2c2..31164b2 100644
--- a/backend/sport/main.go
+++ b/backend/sport/main.go
@@ -5,6 +5,7 @@ import (
 	"net/http"
 	"strconv"
 	"strings"
+	"sync"
 	"time"
 
 	"github.com/PuerkitoBio/goquery"
@@ -29,27 +30,43 @@ func main() {
 // Since the ids are not consecutive, it will take a while to fetch all sport courses.
 // @TODO: find the highest id and iterate over all ids from 0 to highest id
 func fetchAllHtwkSportCourses() []Event {
-	var events []Event
-	for i := 0; i <= 9999; i++ {
-		newEvent, err := fetchHtwkSportCourse("https://sport.htwk-leipzig.de/sportangebote/detail/sport/", i)
-		if err != nil {
-			continue
-		}
-		events = append(events, newEvent...)
 
+	//multithreaded webpage requests to speed up the process
+
+	var maxPageID = 9999
+	var maxThreads = 300
+	var htmlPageArray = make([]*goquery.Document, maxPageID)
+	var url = "https://sport.htwk-leipzig.de/sportangebote/detail/sport/"
+
+	var wg sync.WaitGroup
+	wg.Add(maxThreads)
+
+	for i := 0; i < maxThreads; i++ {
+		go func(i int) {
+			defer wg.Done()
+			for j := i; j < maxPageID; j += maxThreads {
+				doc, err := htmlRequest(url + strconv.Itoa(j))
+				if err == nil {
+					htmlPageArray[j] = doc
+				}
+			}
+		}(i)
 	}
+
+	wg.Wait()
+
+	println("finished fetching all pages")
+
+	//print count of all pages
+
+	var events []Event
 	return events
 }
 
-// fetchHtwkSportCourse fetches the sport course from the given url and id.
-// If the sport course does not exist, it will return an error.
-// If the sport course exists, it will return the sport course.
-// goquery is used to parse the html. The html structure is not very consistent, so it is hard to parse.
-// May be improved in the future.
-func fetchHtwkSportCourse(url string, id int) ([]Event, error) {
-	var events []Event
+func htmlRequest(url string) (*goquery.Document, error) {
+	println("fetching " + url)
 
-	resp, err := http.Get(url + strconv.Itoa(id))
+	resp, err := http.Get(url)
 	if err != nil {
 		return nil, err
 	}
@@ -60,6 +77,18 @@ func fetchHtwkSportCourse(url string, id int) ([]Event, error) {
 		return nil, err
 	}
 
+	println("finished fetching " + url)
+	return doc, nil
+}
+
+// fetchHtwkSportCourse fetches the sport course from the given url and id.
+// If the sport course does not exist, it will return an error.
+// If the sport course exists, it will return the sport course.
+// goquery is used to parse the html. The html structure is not very consistent, so it is hard to parse.
+// May be improved in the future.
+func fetchHtwkSportCourse(doc *goquery.Document) ([]Event, error) {
+	var events []Event
+
 	if doc.Find("h1").Text() == "Aktuelle Sportangebote" {
 		return nil, errors.New("not a sport course page")
 	}
@@ -73,6 +102,11 @@ func fetchHtwkSportCourse(url string, id int) ([]Event, error) {
 		if len(titleParts) > 0 {
 			event.Title = strings.TrimSpace(titleParts[0])
 		}
+
+		if len(titleParts) > 2 {
+			details.Type = strings.TrimSpace(titleParts[len(titleParts)-1])
+		}
+
 		s.NextFiltered("table.eventDetails").Find("tr").Each(func(i int, s *goquery.Selection) {
 			key := strings.TrimSpace(s.Find("td").First().Text())
 			value := strings.TrimSpace(s.Find("td").Last().Text())
@@ -157,6 +191,7 @@ type EventDetails struct {
 	Location     Location
 	Participants Participants
 	Cost         string
+	Type         string
 }
 
 // DateRange represents a start and end date.